Rocket engines, such as those used on space missions, are costly to design and manufacture. In addition, there is a continuing and growing need for rockets capable of carrying payloads to space or near-Earth orbits. Consequently, manufacturers of such rocket engines are constantly seeking new ways to reduce the cost of producing the components which go into a rocket engine.
One such component is the rocket combustion chamber/nozzle assembly within which the propellants of the rocket engine are mixed, cornbusted and accelerated. Because of the extremely high temperatures of the propellants moving through the combustion chamber, the walls of the thrust chamber must be cooled in those applications which require sustained engine firings. Such cooling is typically accomplished by flowing a coolant through tubes or channels which form the inner surface of the combustion chamber.
A typical example of such thrust chambers is shown in U.S. Pat. No. 3,208,132 to Escher, which discloses a rocket chamber produced by forming coolant flow passages within two sheets by an explosive forming process. The formed sheets must be subsequently welded or brazed together to form individual flow passages, and the integrity of these welds is difficult to inspect. U.S. Pat. No. 3,190,070 to Neu discloses a rocket chamber formed from a plurality of pre-formed coolant tubes. The tubes must be manufactured to close tolerances to ensure that the resulting tube bundle adequately shields the structural jacket of the chamber from the combustion products. U.S. Pat. No. 3,595,025 to Stockel et al discloses a rocket chamber liner having grooves which, when mated with a structural jacket, form cooling channels. These grooves must be machined into the liner, and therefore require a significant amount of labor to produce.
What is needed is a method of making a rocket combustion chamber/nozzle assembly which does not require exacting tube tolerances, is less labor intensive than the prior art, and does not incorporate welds or brazes that cannot be readily inspected.